JPH02217290A - thermal transfer sheet - Google Patents

Abstract

PURPOSE:To increase a transfer recording speed and to enhance the image quality and storage stability of a record material by forming a colorant layer containing a specific methine dye on a base film. CONSTITUTION:A colorant layer containing a methine dye represented by general formula (1) (wherein A is hydrogen, a lower alkyl, group, a lower alkoxy group, a lower alkenyl group, an aryl group or a heterocyclic group, R is hydrogen or a lower alkyl group, R' is an aryl group, a halogen atom or a carboxylic acid group or an ester or nitrile group thereof and X is hydrogen, a halogen, a lower alkyl group or a lower alkoxy group) is provided on a base film. Since this methine dye has a sharp yellow color, said dye is suitable for obtaining full color recording showing good color reproducibility by the combination with a proper magenta color and a proper cyan color and, further, since said methine dye is easily sublimable and has high molecular extinction coefficient, recording imparting high color density can be obtained at a high speed without applying large load to a thermal head.

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Object of the Invention (Field of Industrial Application) The present invention relates to a transfer sheet used for sublimation type thermal transfer recording.

(Conventional technology) Conventionally, there has been a demand for technology for color recording facsimile printers, copying machines, television images, etc., and color recording technologies using electrophotography, inkjet, thermal transfer, etc. are being considered.◇ The thermal transfer recording method is It is considered advantageous compared to other methods because the equipment is easy to maintain and operate, and the equipment and consumables are inexpensive.

Thermal transfer methods include a transfer sheeter in which a heat-melting ink layer is formed on a base film, a melting method in which the ink is heated by a heat-sensitive head, and is transferred and recorded onto a recording medium, and a base film is used. There is a sublimation method in which an ink layer containing a sublimable dye is formed on top of the transfer sheet, which is heated by a thermal head to sublimate the dye and then transferred and recorded onto the recording medium. By changing the applied energy, the amount of dye sublimation transfer can be controlled, which facilitates gradation recording and is particularly advantageous for full-color recording.

In thermal transfer recording using the sublimation method, the sublimable dye used in the transfer sheet is extremely important as it has a great effect on the speed of transfer recording, the image quality of the recorded material, and the storage stability. It is necessary to fulfill the following requirements.

■ Easily sublimated under the operating conditions of the thermal recording head.

■Do not thermally decompose under the operating conditions of the thermal recording bed. ■ It must have a favorable hue in terms of color reproduction.

■ High molecular extinction coefficient.

■ Stable against heat, light, moisture, chemicals, etc.

■ The dye itself is easy to synthesize.

■Excellent suitability for inking.

■ There are no safety and health issues.

A dye that satisfies all of the above conditions has not yet been found, and yellow dyes in particular have various drawbacks and have not been found to be satisfactory.

(Problems to be Solved by the Invention) An object of the present invention is to provide a heat-sensitive transfer sheet using a yellow dye that satisfies all of the above conditions.

(b) Structure of the Invention (Means for Solving Problems) The heat-sensitive transfer sheet of the present invention has - on the base film - pattern hole (1) (wherein A is hydrogen, a lower alkyl group, a lower alkoxy group, lower alkenyl group, aryl group, vIL ring group, R is hydrogen, lower alkyl group, Bl is aryl group, halogen atom, carboxylic acid, ester group thereof, or nitrile group 1, X is hydrogen, lower alkyl group, lower alkoxy 2I!i)) is characterized by having a coloring layer containing a methine dye.

Specific examples of the methine dyes indicated by the above-mentioned symbol are as follows.

Exemplary methine dyes Hs 0H.

CH.

CH.

The dye represented by formula (I) used in the heat-sensitive transfer sheet of the present invention can be prepared, for example, by the following method. can be built.

That is, an N%N-disubstituted aniline compound represented by the formula (wherein, A compound represented by the general formula (where X%R,A is synonymous with υ) was obtained, and this compound was given the general
[: In the formula, R/ has the same meaning as in general formula (1). ] When the active methylene compound represented by is reacted in a basic atmosphere, the target compound represented by -Monken (υ) is obtained.

In order to produce the heat-sensitive transfer sheet of the present invention, in order to provide a color material layer containing the dye represented by the above-mentioned hole (I) on the base film, the dye is dissolved in a bath together with a binder in a medium. This can be easily carried out by coating the ink prepared in 11 by separating it into fine particles onto the base film and drying it.

Binders for preparing the ink include, for example, cellulose-based or starch-based compounds, water-soluble resins such as acrylic acid-based resins; acrylic resins, methacrylic resins, polystyrene, polycarbonate, polysulfone, polyethersulfone, polyvinyl butyral. , ethyl cellulose, acetyl cellulose, and other organic solvents or water-soluble resins. Also, as a medium for the ink t-1, #a, water; alcohols such as methyl alcohol, isobutyl alcohol, and isobutyl alcohol. Aromatic hydrocarbons such as ethyl cellosolve, ethyl cellosolve, etc.) Aromatic hydrocarbons such as luene, xylene, chlorobenzene and their decagenides; Esters such as ethyl acetate and butyl acetate; Acetone, methyl ethyl ketone, methyl Ketones such as isobutyl ketone and cyclohexanone; aliphatic hydrocarbon halides such as methylene chloride, chloroform, and trichloroethylene; ethers such as tetrahydro7rane and dioyasane; polar solvents such as N,N-dimethylformamide, and N-methylpyrrolidone etc.

In addition to the above-mentioned components, the above ink also contains organic and inorganic non-sublimable fine particles, dispersants, antistatic agents, antiblocking agents, antifoaming agents, antioxidants, viscosity modifiers, etc. as necessary. The base film on which the ink is applied for manufacturing the transfer sheet of the present invention may be thin paper such as condenser paper or glassine paper; 4. Good plastic film is available. The thickness of these base films is suitably in the range of 3 to 50 cm. Among these base films, polyethylene terephthalate film is preferred from the viewpoint of mechanical strength, solvent resistance, economical efficiency, etc. Even so, the heat resistance is not as high as that of light, and the running performance of the thermal head is insufficient. but,
On the opposite side of the polyethylene terephthalate film to the side on which the colorant layer is provided, a surfactant, heat-resistant particles with high lubricity (for example, granular silica, inorganic particles such as titanium oxide, granular benzoguanidine resin, organic particles such as fluororesin, etc.) are added. ), etc., the running properties of the thermal head can be improved.

As a method of applying ink to the base film, a reverse roll coater, a reverse roll coater, an air doctor coater, and the like can be used. The thickness is preferably in the range of 0.1 to 5 μm.

The thermal transfer sheet of the present invention can utilize not only a thermal head but also infrared rays, laser light, etc. as a heating means.

(Operations and Effects of the Invention) The methine dye represented by the above-mentioned hole (I) used in the heat-sensitive transfer sheet of the present invention has a clear yellow color t.
V, it is suitable for obtaining full-color recording with good color reproducibility by combining with appropriate magenta and cyan colors.It is also easy to sublime and has a large molecular extinction coefficient, so it does not place a large burden on the thermal head. It is possible to obtain high-speed recordings with high color density without using Furthermore, since it is stable against heat, moisture, chemicals, etc., it does not undergo thermal decomposition during transfer recording, and the resulting recording has excellent storage stability, especially light resistance. In addition, since this pigment has good solubility in organic solvents and good dispersibility in water, it is easy to make Y4 ink with high concentration that is uniformly dissolved or dispersed. A heat-sensitive transfer sheet having a coloring material layer coated uniformly at a high concentration is obtained, and by using this heat-sensitive transfer sheet, recording with good uniformity and chromaticity can be obtained.

(Example) The present invention will be described in more detail with reference to Examples below, but the present invention is not limited to the Examples.Example 1 (a) Synthesis of methine dye (Exemplary Compound &1) N,N-diallylaniline (oil) is synthesized from aniline and diallyl bromide using caustic soda, and this is subjected to a formylation reaction using a prescribed method to easily obtain N,N-diallylaminobenzaldehyde (oil). .

1 equivalent per equivalent of the aldehyde obtained in this way.
．． After adding 2 equivalents of malonitrile and dissolving them in amyl alcohol, and further adding a small amount of piperidine, the mixture was heated under reflux in a 130° C. oil bath for about 1 hour. The reaction solution was cooled on ice, and the precipitated orange crystals were filtered, washed with methanol, and then dried. Melting point is 88-89.5
℃ and the λ leg x in acetone was 430 nm.

(Preparation of ink) Using the methine dye synthesized as described above, a mixture having the following composition was treated in a paint conditioner for 10 minutes to prepare an ink.

The above methine dye 10J + cellulose acetate (Daicel Chemical Co., Ltd. trade name L-30) 10j combination
Total 100JI? 1. Preparation of transfer sheet Using the above ink t-wire paper, transfer a 2'L 9 polyethylene terephthalate film (6'
A transfer sheet was obtained by coating the film on the surface of the film (IJs) and drying it.

The heat-resistant lubricity treatment of the polyethylene terephthalate film used was carried out by adding 8 parts by weight of a polycarbonate resin having a repeating structural unit represented by the formula to the polyethylene terephthalate film, and a phosphate ester surfactant (a product of Daiichi Kogyo Seiyaku Co., Ltd.). The test was carried out by applying 91 parts by weight of toluene (Plysurf A-208B) using an applicator and drying (dry film thickness: 0.5 μm).

2) Preparation of image receptor Saturated polyester resin
-220) 103, 0.5 parts by weight of amine-modified silicone (trade name KF393, Shin-Etsu Chemical Co., Ltd.),
A liquid consisting of 15 parts by weight of methyl ethyl ketone and 15 parts by weight of xylene is added to synthetic paper (trade name: Yubo FP, Oji Yuka Co., Ltd.).
G150) with a wire parr, dried (dry film summary 5 s n-), and further heated at 100°C in an open environment for 3
The entire image receptor was fabricated by heat treatment for 0 minutes.

(E) Transfer recording The ink me side of the transfer sheet prepared as described above (
The coloring material layer) was prepared as described above and layered on the image receptor,
When recording was performed using a thermal head under the following conditions, a clear yellow color with a uniform color density of 1.9 was obtained. ) Linear density of main scanning and sub-scanning: 8 dots/- Recording power
0.25W/dot head heating time 10 inertia Transfer recording was performed using the same method as above. Each record obtained was #
It was a clear yellow color with the color density as shown in Table I10. Furthermore, the results of the light fastness test and dark storage test similar to those in Example 1 for each of the obtained records were good. Ta.

(hereinafter referred to as "Kinpaku") The light resistance test of the obtained records was conducted using a carbon arc fade meter (trade name of Suga Test Instruments Co., Ltd.) at a black panel temperature of 63±2℃, and it was found that almost no light resistance was observed even after 40 hours of irradiation. No discoloration or fading90.Furthermore, the transfer sheet and recording were stable against heat and moisture, and had excellent storage stability in the dark.

Examples 2 to 18 Instead of the methine dye in Example 1, the methine dye from Cypress described in Section 1-2 was synthesized in the same manner, and each of the obtained dyes was used to synthesize the methine dye in Example 1. In the same way, apply ink tv/4n and explode the transfer sheet.

It was carried out using each of the obtained transfer sheets and the same image receptor as in Example 1. 111 Procedural Amendment (Salmon) June 9, 1999 1゜2゜3゜Indication of case 1999 Patent application No. Name of invention Relationship with case of person who amends thermal transfer sheet Patent applicant No. 37841 4゜廿 (600) 248+ The "Claims" column of the specification subject to amendment and (1) the "Claims" of the specification are corrected as shown in the attached sheet.

(2) Page 5, line 2 of the specification.

"Lower alkyl group" was corrected to "halogen lower alkyl group".

``1゜ Separate paper base film with the general formula (where A represents hydrogen, a lower alkyl group, a lower alkoxy group, a lower alkenyl group, an aryl group, a heterocyclic residue, and R represents hydrogen, a lower alkyl group, R' represents an aryl group, a halogen atom, a carboxylic acid and its ester group, or a nitrile group, and X represents hydrogen, a halogen lower alkyl group, or a lower alkoxy group. A heat-sensitive transfer sheet characterized by having.

Claims (1)

[Claims] 1.) On the base film, there is a general formula (1) ▲ mathematical formula, chemical formula, table, etc. ▼ ... (1) (wherein A is hydrogen, a lower alkyl group, Represents a lower alkoxy group, lower alkenyl group, aryl group, or heterocyclic residue, R represents hydrogen, a lower alkyl group, R' represents an aryl group, a halogen atom, a carboxylic acid and its ester group, or a nitrile group, and X represents 1. A heat-sensitive transfer sheet comprising a coloring material layer containing a methine dye represented by hydrogen, a lower alkyl group, or a lower alkoxy group.